<?php
    // +----------------------------------------------------------------------
    // | ThinkPHP [ WE CAN DO IT JUST THINK ]
    // +----------------------------------------------------------------------
    // | Copyright (c) 2006~2017 http://thinkphp.cn All rights reserved.
    // +----------------------------------------------------------------------
    // | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
    // +----------------------------------------------------------------------
    // | Author: zhangyajun <448901948@qq.com>
    // +----------------------------------------------------------------------
    namespace think\paginator\driver;

    use think\Paginator;

    class Bootstrap extends Paginator {
        /**
         * 渲染分页html
         * @return mixed
         */
        public function render() {
            if ($this->hasPages()) {
                if ($this->simple) {
                    return sprintf('<ul class="pager">%s %s</ul>', $this->getPreviousButton(), $this->getNextButton()
                    );
                } else {
                    return sprintf('<ul class="pagination">%s %s %s</ul>', $this->getPreviousButton(), $this->getLinks(), $this->getNextButton()
                    );
                }
            }
        }

        /**
         * 上一页按钮
         * @param string $text
         * @return string
         */
        protected function getPreviousButton($text = "&laquo;") {
            if ($this->currentPage() <= 1) {
                return $this->getDisabledTextWrapper($text);
            }
            $url = $this->url($this->currentPage() - 1
            );
            return $this->getPageLinkWrapper($url, $text);
        }

        /**
         * 生成一个禁用的按钮
         * @param  string $text
         * @return string
         */
        protected function getDisabledTextWrapper($text) {
            return '<li class="disabled"><span>' . $text . '</span></li>';
        }

        /**
         * 生成普通页码按钮
         * @param  string $url
         * @param  int    $page
         * @return string
         */
        protected function getPageLinkWrapper($url, $page) {
            if ($page == $this->currentPage()) {
                return $this->getActivePageWrapper($page);
            }
            return $this->getAvailablePageWrapper($url, $page);
        }

        /**
         * 生成一个激活的按钮
         * @param  string $text
         * @return string
         */
        protected function getActivePageWrapper($text) {
            return '<li class="active"><span>' . $text . '</span></li>';
        }

        /**
         * 生成一个可点击的按钮
         * @param  string $url
         * @param  int    $page
         * @return string
         */
        protected function getAvailablePageWrapper($url, $page) {
            return '<li><a href="' . htmlentities($url) . '">' . $page . '</a></li>';
        }

        /**
         * 下一页按钮
         * @param string $text
         * @return string
         */
        protected function getNextButton($text = '&raquo;') {
            if (!$this->hasMore) {
                return $this->getDisabledTextWrapper($text);
            }
            $url = $this->url($this->currentPage() + 1);
            return $this->getPageLinkWrapper($url, $text);
        }

        /**
         * 页码按钮
         * @return string
         */
        protected function getLinks() {
            if ($this->simple) {
                return '';
            }
            $block  = [
                'first'  => null,
                'slider' => null,
                'last'   => null
            ];
            $side   = 3;
            $window = $side * 2;
            if ($this->lastPage < $window + 6) {
                $block['first'] = $this->getUrlRange(1, $this->lastPage);
            } elseif ($this->currentPage <= $window) {
                $block['first'] = $this->getUrlRange(1, $window + 2);
                $block['last']  = $this->getUrlRange($this->lastPage - 1, $this->lastPage);
            } elseif ($this->currentPage > ($this->lastPage - $window)) {
                $block['first'] = $this->getUrlRange(1, 2);
                $block['last']  = $this->getUrlRange($this->lastPage - ($window + 2), $this->lastPage);
            } else {
                $block['first']  = $this->getUrlRange(1, 2);
                $block['slider'] = $this->getUrlRange($this->currentPage - $side, $this->currentPage + $side);
                $block['last']   = $this->getUrlRange($this->lastPage - 1, $this->lastPage);
            }
            $html = '';
            if (is_array($block['first'])) {
                $html .= $this->getUrlLinks($block['first']);
            }
            if (is_array($block['slider'])) {
                $html .= $this->getDots();
                $html .= $this->getUrlLinks($block['slider']);
            }
            if (is_array($block['last'])) {
                $html .= $this->getDots();
                $html .= $this->getUrlLinks($block['last']);
            }
            return $html;
        }

        /**
         * 批量生成页码按钮.
         * @param  array $urls
         * @return string
         */
        protected function getUrlLinks(array $urls) {
            $html = '';
            foreach ($urls as $page => $url) {
                $html .= $this->getPageLinkWrapper($url, $page);
            }
            return $html;
        }

        /**
         * 生成省略号按钮
         * @return string
         */
        protected function getDots() {
            return $this->getDisabledTextWrapper('...');
        }
    }
